1. The Field of the Invention
This invention relates to novel filaments (or fibers) for toothbrushes. More precisely, this invention relates to an improved filament for cleaning the oral cavity and polishing the teeth. The present invention also relates to a method of cleaning the oral cavity and polishing the teeth utilizing a brush containing said novel, improved filaments.
2. Description of the Prior Art
Commercially available toothbrushes typically have elongated handles with monofilament or co-extruded filament bristles mounted on a generally flattened, laterally-facing head at the distal end of a handle. The thin flexible bristles are smooth members of which the ends are cut off at right angles and are often rounded to dome-like tips. Toothbrushes of this type and the mechanism of toothbrushing play an important part in oral hygiene. It has been shown unequivocally that toothbrushing is instrumental in reducing dental decay. See, for example, Fosdick, L. S. J. Am. Dent. Assoc., 40, 133 (1950). Furthermore, regular brushing with a cosmetic dentifrice further reduces the incidence of decay among susceptible subjects.
Regular toothbrushing with a dentifrice is further touted as being effective in reducing or preventing periodontal disease, removing food debris, and massaging the gums. Most commercial dentifrices include a mild abrasive powder to improve the composition's ability to remove adherent soiling matter, to free accessible plaque, to dislodge accessible debris and to remove superficial stain from the teeth.
Attempts have been made to embed abrasive materials or adhere abrasive materials on fiber strands for use in toothbrushes. See, for example, U.S. Pat. No. 1,470,710 to Davis and U.S. Pat. No. 5,249,961 to Hoagland. These attempts did not meet the needs of the consumer due to their tendency to (a) lose embedded abrasive; (b) abrade the gums; and (c) lack mechanical durability. Also, U.S. Pat. No. 3,618,154 to Muhler et al. describes a one piece integrally molded brush with tapered bristles. The entire brush/bristle combination is made of plastic containing up to 30% (wt.) abrasive material. This attempt has not met with success due to the difficulty of molding such a brush. In addition, molded, i.e. unoriented, bristles tend to leave poor mechanical properties, e.g. stiffness, bend recovery, etc., and tend to splay.
Also, abrasive materials have been added to the elastomeric material used in prophylactic cleaning cups. These power driven cups are used to polish and clean the teeth by a highly skilled dental practitioner. See, for example, U.S. Pat. No. 3,977,084 to Sloan and U.S. Pat. No. 5,273,559 to Hammar et al.
Attempts have been made to provide a toothbrush with a roughened irregular surface to make the bristle wall more abrasive. See, for example, U.S. Pat. No. 3,671,381 to Hansen. This attempt requires costly subsequent etching of the bristle with caustic or high pressure steam and results in a loss of mechanical properties. Others have attempted to provide bristles with more regular abrasive protrusions. See, for example, U.S. Pat. No. 4,373,541 to Nishioka. These attempts have not met with commercial success due to the inconvenience and increased processing cost associated with molding each bristle individually. Furthermore, these bristles exhibit extremely poor mechanical properties.
Abrasive containing filament materials are widely used in non-oral care, industrial applications such as metal polishing, street sweeping, vacuum cleaner brushes, etc. See, for example, U.S. Pat. Nos. 2,336,797 to Maxwell; U.S. Pat. No. 2,609,642 to Peterson; U.S. Pat. No. 2,711,365 to Price et al; U.S. Pat. No. 2,712,987 to Storrs et al; U.S. Pat. No. 2,836,517 to Gruber et al; U.S. Pat. No. 2,920,947 to Burk et al; U.S. Pat. No. 3,115,401 to Downing et al; U.S. Pat. No. 3,384,915 to Rands; U.S. Pat. No. 3,556,752 to Wilson; U.S. Pat. No. 3,577,839 to Charvat et al; U.S. Pat. No. 3,696,563 to Rands; U.S. Pat. No. 4,305,234 to Pichelman; U.S Pat. No. 4,627,950 to Matsui; U.S. Pat. No. 4,630,407 to Rhodes; U.S. Pat. No. 4,704,823 to Steinback; U.S. Pat. No. 5,016,311 to Young et al; U.S. Pat. No. 5,030,496 to McGurran; U.S. Pat. No. 5,045,091 to Abrahamson et al; U.S. Pat. No. 5,056,267 to Nicely et al; U.S. Pat. No. 5,083,840 to Young; U.S. Pat. No. 5,108,155 to Hettes et al; U.S. Pat. No. 5,211,725 to Fowlie et al; and, U.S. Pat. No. 5,227,229 to McMahan et al.